Currently the most widely practiced industrial scale production method for hydrogen peroxide is an indirect reaction of hydrogen and oxygen employing alkylanthraquinone as the working material. In a first catalytic hydrogenation step, the alkylanthraquinone, dissolved in a working solution comprising organic solvents (e.g. diisobutylcarbinol and methyl naphthalene), is converted to alkylanthrahydroquinone. In a separate autoxidation step, this reduced compound is oxidized to regenerate the alkylanthraquinone and yield hydrogen peroxide. Subsequent separation by aqueous extraction, refining, and concentration operations are then employed to give a merchant grade product. In order to be economical, the alkylanthraquinone process requires large scale production of hydrogen peroxide to justify the cost of the subsequent extraction and purification of the hydrogen peroxide.
The direct production of hydrogen peroxide from hydrogen and oxygen is one route to produce hydrogen peroxide without the costly separation and purification associated with the alkylanthraquinone process. However, there are problems associated with this, such as working with combustible mixtures of hydrogen and oxygen in the gas phase, and the low solubility of hydrogen and oxygen at relatively low pressures in water.
It would be convenient and a savings to be able to produce hydrogen peroxide without the complex processes associated with large scale production, or using processes that require continuous addition of chemicals which would require storage and careful handling. In addition, a simpler process that would enable economic production of hydrogen peroxide on a small scale and the periodic production of hydrogen peroxide on an as needed basis can provide for usage of hydrogen peroxide in areas where it would otherwise be inconvenient, such as the need to buy and store hydrogen peroxide.
An aspect of the problem is the separation and recovery of hydrogen peroxide from any chemicals used in the production of the hydrogen peroxide. For small scale processes with periodic production, it is desired to recover substantially all of the intermediate chemicals in use in the process beyond water and air.